Dipole antenna

Abstract

Disposing an additional sleeve-shaped structure, which is also called a sleeve, on a first radiator of both resonant radiators of a dipole antenna so that a cavity is formed between the additional radiator and a second resonant radiator of the dipole antenna. An effective bandwidth of the dipole antenna is increased significantly by a capacitance effect caused by the cavity so that more channels can be received by a general digital television broadband antenna while the dipole antenna is applied on the digital television broadband antenna.

1. A dipole antenna formed on a substrate for transmitting a signal, the dipole antenna comprising:
 a first radiator; 
 a second radiator resonating with the first radiator for transmitting the signal; and 
 a sleeve-shaped structure having an opening and a closed bottom portion connected to the second radiator, wherein the first radiator is inserted in the sleeve-shaped structure through the opening and disconnected from the closed bottom portion of the sleeve-shaped structure. 
 
   
   
     2. The dipole antenna of  claim 1  formed on a printed circuit board (PCB). 
   
   
     3. The dipole antenna of  claim 1  wherein the length of the first radiator is about a quarter of the wavelength of the signal fed into the first radiator. 
   
   
     4. The dipole antenna of  claim 1  wherein the length of the second radiator is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     5. The dipole antenna of  claim 1  wherein a measurement of the length of the inner-side of the sleeve-shaped structure is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     6. The dipole antenna of  claim 1  further comprising a connector extending from the sleeve-shaped structure. 
   
   
     7. The dipole antenna of  claim 6  further comprising a conductive wire connected to an end of the first radiator and an end of the connector for feeding the signal into the first radiator and the second radiator. 
   
   
     8. A dipole antenna formed on a substrate and utilized for transmitting a signal, the dipole radiator comprising:
 a first radiator having a first end and a second end, the second end comprising a first branch and a second branch; 
 a second radiator having a first end and a second end, the second end comprising a third branch and a fourth branch; and 
 a sleeve-shaped structure having a closed portion connected to a first beam and a second beam to form a first opening, wherein a first end of the second radiator is connected to the closed portion of the sleeve-shaped structure, and the first radiator is inserted in the sleeve-shaped structure through the first opening and disconnected from the closed portion of the sleeve-shaped structure. 
 
   
   
     9. The dipole antenna of  claim 8  wherein the sum of the lengths of the first radiator and the first branch is about a quarter of the wavelength of the signal fed into the first radiator. 
   
   
     10. The dipole antenna of  claim 8  wherein the sum of the lengths of the first radiator and the second branch is about a quarter of the wavelength of the signal fed into the first radiator. 
   
   
     11. The dipole antenna of  claim 8  wherein the sum of the lengths of the second radiator and the third branch is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     12. The dipole antenna of  claim 8  wherein the sum of the lengths of the second radiator and the fourth branch is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     13. The dipole antenna of  claim 8  wherein the sum of the lengths of the first beam, the bottom, and the second beam is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     14. The dipole antenna of  claim 8  further comprising a third beam and a fourth beam respectively connected to the closed portion of the sleeve-shaped structure for forming a second opening, and the second radiator inserted in the second opening. 
   
   
     15. The dipole antenna of  claim 14  wherein the sum of the lengths of the third beam, the closed portion, and the fourth beam is about a quarter of the wavelength of the signal fed into the second radiator. 
   
   
     16. The dipole antenna of  claim 14  further comprising a connector extending from the first opening and the second opening. 
   
   
     17. The dipole antenna of  claim 8  further comprising a conductive wire connected to the first end of the first radiator and an end of the connector and utilized for feeding the signal into the first radiator and the second radiator. 
   
   
     18. The dipole antenna of  claim 8  formed on a printed circuit board. 
   
   
     19. The dipole antenna of  claim 8  wherein the first branch extends from the second end of the first radiator and bends toward the first end of the first radiator. 
   
   
     20. The dipole antenna of  claim 8  wherein the second branch extends from the second end of the first radiator and bends toward the first end of the first radiator. 
   
   
     21. The dipole antenna of  claim 8  wherein the third branch extends from the second end of the second radiator and bends toward the first end of the second radiator. 
   
   
     22. The dipole antenna of  claim 8  wherein the fourth branch extends from the second end of the second radiator and bends toward the first end of the second radiator.